The present disclosure discusses a circuit including a memristor. In one example the circuit may be used in a memory array. In one example a memory array including memristors is used as a memory in an electronic device, such as but not limited to, a fluid ejection device.
A memristor is a device that changes resistance depending upon a potential difference that has been applied across the memristor during a switching event. Each memristor has a switching voltage that refers to a voltage used to switch the state of the memristor. When the supplied voltage is greater than the memristor switching voltage, the memristor switches state, e.g.: from ON state to OFF state or from OFF state to ON state. In an ON state the memristor has a relatively lower resistance and in the OFF state the memristor has a relatively higher resistance. As the resistance changes upon a switching event, the memristor may be used as a memory.
Switching a memristor to an ON state, having a low resistance, is known as setting the memristor. A memristor may be set by applying a potential difference above a first threshold to the memristor. Switching a memristor to an OFF state, having a high resistance, is known as resetting the memristor. A memristor may be reset by applying a potential difference below a second threshold.
In the case of a bi-polar memristor, the first threshold and second threshold are potential differences of opposite polarity. Thus, for example, a positive potential difference above a first threshold, may SET the memristor to an ON state; and a negative potential difference below a second threshold may RESET the memristor to an OFF state. Thus, a voltage source capable of delivering both positive and negative polarities of voltage may be used to SET and RESET the memristor.